236 JOURNAL OF COSMETIC SCIENCE (18) (19) (20) (21) (22) (23) Absorption: Principles, Fundamentals and Applications, R.L. Bronaugh and H. I. Maibach, Eds. (CRC Press, Boca Raton, FL, 1991), pp. 67-83. (2) J. R. Trevithick and K. P. Mitton, Topical application and uptake of vitamin E acetate by the skin and conversion to free vitamin E, Biochem. Molec. Biol. Int., 31, 869-877 (1993). (3) E. P. Norkus, G. F. Bryce, and H. N. Bhagavan, Uptake and bioconversion of o•-tocopheryl acetate to o•-tocopherol in skin of hairless mice, Photochem. Photobid., 57, 613-615 (1993). (4) M. Rangarajan and J. L. Zatz, Kinetics of permeation and metabolism of o•-tocopherol and o•-tocoph- eryl acetate in micro-Yucatan pig skin, J. Cosmet. Sci., 52, 35-50 (2001). (5) D. S. Alberts, R. Goldman, M.-J. Xu, R. T. Dorr, J. Quinn, K. Welch, J. Guillen-Rodriguez, M. Aickin, Y.-M. Peng, L. Loescher, and H. Gensler, Disposition and metabolism of topically adminis- tered o•-tocopherol acetate: A common ingredient of commercially available sunscreens and cosmetics, Nutr. Cancer, 26, 193-201 (1996). (6) W. Meyer and K. Neurand, The distribution of enzymes in the skin of the domestic pig, Lab. Animals, 10, 237-247 (1976). (7) D. Dupuis, A. Rougier, R. Roguet, and C. Lotte, The measurement of the SC reservoir: A simple method to predict the influence of vehicles on in-vivo percutaneous absorption, Br. J. Dermatol., 115, 233-238 (1986). (8) S.W. Collier, N.M. Sheik, A. Sakr, J.L. Lichtin, R.F. Stewart and R.L. Bronaugh, Maintenance of skin viability during in vitro percutaneous absorption/metabolism studies, Toxicol. AppL Pharmacol., 99, 522-533 (1989). (9) R. Dulbecco and M. Vogel, Plaque formation and isolation of pure lines with poliomyelitis viruses,J. Exp. Med., 99, 167-182 (1954). (10) R.L. Bronaugh and R.F. Stewart, Methods for in vitro percutaneous absorption studies. III. Hydro- phobic compounds, J. Pharm. Sci., 73, 1255-1258 (1984). (l l) G.P. Kushla, Studies of lidocaine permeation through hairless mouse skin from propylene glycol-water mixtures, M.S. thesis, Rutgers University, Piscataway, New Jersey (1986). (12) M. Rangarajan, Effect of formulation on the topical delivery and metabolism of alpha-tocopheryl acetate and permeation of alpha tocopherol, Ph.D. dissertation, Rutgers University, Piscataway, New Jersey (2000). (13) R.C. Wester and H.I. Maibach, Absorption of tocopherol into and through human skin, Cosmet. Toilerr., 112, 53-57 (1997). (14) W. Gehring, J. Fluhr, and M. Gloor, Influence of vitamin E acetate on stratum corneum hydration, Arzneim.-Forsch./Drug Res., 48(II), 772-775 (1998). (15) M. Kamimura and T. Matsuzawa, Percutaneous absorption of o•-tocopheryl acetate, J. Vitaminol., 14, 150-159 (1968). (16) K. Tojo and A.C. Lee, Bioconversion of a provitamin to vitamins C and E in skin,J. Soc. Co, met. Chem., 38, 333-339 (1987). (l 7) Z. Nabi, A. Tavakkol, N. Soliman, and T.G. Polefka, Bioconversion of tocopheryl acetate to tocopherol in human skin: Use of human skin organ culture models, Poster presentation, Colgate-Palmolive Co., Piscataway, New Jersey (1999). M. Trotta, S. Morel and M. R. Gasco, Effect of oil phase composition on the skin: Permeation of felodipine from o/w microemulsion, Pharmazie, 52, 50-53 (1997). M.R. Gasco, M. Gallarate, and F. Pattarino, In-vitro permeation of alzelaic acid from viscosized microemulsions. Int. J. Pharm., 69, 193-196 (1991). D.W. Osborne, A.J.I. Ward, and K.J. O'Neill, Microemulsions as topical drug delivery vehicles: In-vitro transdermal studies of model hydrophilic drugs,J. Pharm. Pharmacol., 43, 451-454 (1991). R. Natsuki, Y. Morita, S. Osawa, and Y. Takeda, Effect of liposome size on penetration ofd/-tocopherol acetate into skin, Biol. Pharm. Bull., 19, 758-761 (1996). M.C. Martini, M.F. Bobin, F. Calllaud, and J. Cotte, Role of micro-emulsions in percutaneous absorption of o•-tocopherol, J. Pharm. Belg., 39, 348-354 (1984). G.M.J. Beijersbergen van Henegouwen, H.E. Junginger, and H. de Vries, Hydrolysis of RRR-o•- tocopheryl (vitamin E acetate) in the skin and its UV protecting activity (an in vivo study with the rat), J. Photochem. Photobiol. B, 29, 45-51 (1995).

j. Cosmet. Sci., 52, 237-250 (July/August 2001) Development of a device to measure human hair luster YUTAKA TANGO and KOICHI SHIMMOTO, KOSt• Corporation, Research & Development Division, Fundamental Research Laboratory, 1-18-4 Azusawa, Itabashi-ku, Tokyo 174-0051, Japan. Accepted for publication April 15, 2001. Synopsis Evaluating human hair luster is important in developing effbctive hair care products. Many methods of measuring human hair luster have been proposed, but most have major disadvantages: some require cutting the subject's hair, some utilize bulky equipment, and some take much time. A device that does not impose excessive burden on the subject and hair, but can easily and conveniently measure human hair luster, has not yet been developed. Overcoming the disadvantages of the traditional method, our new device can measure luster accurately without cutting the hair. Neither the subject's hairstyle nor its color influences the measurements. The device is small, and the time required for measurement is only 0.2 sec. The hair of 84 subjects was evaluated using this device, and there was a high correlation between the sensory score and the measurements obtained. INTRODUCTION Luster is an extremely important factor in evaluating the health of human hair and the effectiveness of its care. Moreover, hair luster is one of the esthetic standards for judging hair, and is important in evaluating hair-finishing cosmetics. Many methods of mea- suring human hair luster have been proposed some utilize goniophotometric meter measurements and calculation of the ratio of specular reflection and diffuse reflection (1). Others analyze hair luster by image processing, using a TV camera to capture an image of a hairstyle and dividing it into three planes of red, green, and blue (2). However, these methods have disadvantages: The goniophotometric method requires cutting of the subject's hair to use as a sample, and the reflective characteristics obtained from a single hair sample do not necessarily reflect the state of luster when human hair is gathered. The TV-camera method is influenced by the subject's hairstyle or head shape, and measurement takes a considerable amount of time. The increasing prevalence of dyed or bleached hair has made measurement of hair luster even more difficult. To overcome these disadvantages, we developed a new measurement device. In this study, the optical reflective process in human hair was assumed to be consistent with the dichromatic reflection model (DRM) of Shafer (3), and so verification was performed and a measurement theory was established. The device based on our theory was then actually developed, and human hair luster was evaluated. 237